Battle of Nanpi

The Battle of Nanpi occurred from January to February 205 AD when Cao Cao's forces defeated and slew his former ally Yuan Tan, the son of Yuan Shao. Yuan Tan had betrayed Cao Cao after enlisting his help in defeating his brother Yuan Shang at Ye, leading to Cao Cao besieging and slaying him at Nanpi.

Background
Following the death of Yuan Shao in 202 AD, he chose his youngest son Yuan Shang as his heir, passing over his other sons Yuan Tan and Yuan Xi. In 204 AD, Yuan Tan decided to turn to his father's former ally and enemy Cao Cao for assistance against his brother, as his strategist Guo Tu had advised him to utilize Cao Cao's force to defeat his brother before turning on Cao Cao and slaying him. Yuan Tan and Cao Cao's combined armies defeated Yuan Shang in the Battle of Jizhou, and Cao Cao conquered Ji Province for himself. Cao Cao gave his daughter to Yuan Tan in marriage to solidify their alliance, but Yuan Tan took command of many of Yuan Shang's troops and attempted to betray Cao Cao by taking Jizhou from him. Cao Cao immediately had his daughter divorce Yuan Tan and marched to Yuan Tan's stronghold of Pingyuan. Yuan Tan unsuccessfully petitioned Jing Province warlord Liu Biao for aid, whereupon he fled to Nanpi, where he was besieged.

Campaign
Cao Cao sent his general Xu Huang to open the battle against Yuan Tan, who slew Yuan Tan's general Peng An in a duel. Yuan Tan then fled into Nanpi and had Xin Ping arrange a surrender deal with Cao Cao, but Cao Cao refused to accept the surrender and also failed to convince Xin Ping to join his brother Xin Pi in serving him. Upon Xin Ping's return, Yuan Tan berated him for his failure and for his brother's defection to Cao Cao, upon which Xin Ping fell ill and died. Yuan Tan then attempted another sortie at the behest of Guo Tu, but the attack failed and multitudes of peasantry driven into the battlefield were slain. Cao Hong himself rode out to battle and slew Yuan Tan, while Guo Tu was killed by several arrows as he attempted to retreat to the city walls. Nanpi, whose moat was filled with the dead, fell to Cao Cao, and he had Guo Tu's family massacred, while Li Fu persuaded him not to sack the city. Shortly after, Yuan Xi's generals Jiao Chu and Zhang Neng arrived with their armies and surrendered to Cao Cao, joining his ranks; Cao Cao also recruited the Qingzhou officer Wang Xiu into his ranks.